Re: Use of o2 cell data in CCR dive logs
Hi Willem, On Oct 13, 2014, at 11:37 AM, Willem Ferguson wrote: Hope you do not mind me changing the topic title. No problem. Thank you very much for your response. The philosophy here is to get the system working for a fully logged CCR system and then to expand this foundation to others. I think you and I disagree on what makes a foundation good to build on. My concern is the code that you're writing looks like it's very specifc to one or two CCRs, and adding further ones in the future will be more difficult because of this. Looking at the patch you've generated so far I could see it growing into a huge amount of code with lots of code paths specific to particular CCRs, all deep in the decompression calculations.That seems like it could grow into a maintainance problem. One of the important things a CCR diver wants to know is to assess the accuracy of the oxygen management system. As a fellow CCR diver I don't have it that at the top of my priority list, but that might be just me. Regardless, I addressed that. I wasn't saying to throw that data away. Just that it would only be used for reference and fault finding (as you describe) once the dive has been initially imported. Of course, code talks, and you're the one writing the code, but I'm interested in helping where / when I can. Paul ___ subsurface mailing list subsurface@subsurface-divelog.org http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
Re: Use of o2 cell data in CCR dive logs
Paul, On 13/10/2014 12:19, Paul Sargent wrote: I hope everyone will forgive a recent subscriber and lurker stating an opinion, but I wonder if this is going down the wrong road. I promised Dirk I'd get involved a while back and never did - so here goes nothing. You're assuming that the cell data provided in a CCR log is: a) interpretable. b) present. For example: If you get a log from a Shearwater predator or petral (used on JJs, rEvos, etc) you'll find that the logged values are the millivolt readings from the cells. You can only turn these into ppO2 readings if you also have the cell calibration data (Also in the memory dump, but not in the CSV or XML exported by Shearwater Desktop). You have to use the ppO2 value calculated by the computer during the dive. Paul Hope you do not mind me changing the topic title. Thank you very much for your response. The philosophy here is to get the system working for a fully logged CCR system and then to expand this foundation to others. The Poseidon logs po2 values (as well as cylinder pressures!). The APD (which logs po2 pressures for 3 sensors) is probably next on the list, but carries a different type of complexity with it. The Shearwater would probably be number 3 on the list and a good amount of discussion is required to start on this. So you will hear a lot about logging Shearwater CCR dives. One of the important things a CCR diver wants to know is to assess the accuracy of the oxygen management system. By how much did the sensors differ and when or where during the dive did significant differences occur? That is basic towards assessing the accuracy of the system and to detect cells that are starting to decay. Therefore the importance of recording sensor values if they are provided in the log file from a particular CCR system. The APD as well as the Poseidon vendor-supplied software allow this and one would like to make Subsurface as attractive as possible for CCR users by making this a real alternative to vendor software. Hope this makes sense. Kind regards, willem ___ subsurface mailing list subsurface@subsurface-divelog.org http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
